Review Question - QID 105821

If a previous chest radiograph is not available for review, a CT scan to identify any concerning features and determination of the lesion's exact size is the next best step in management of an incidentally discovered solitary pulmonary nodule.

Incidentally discovered solitary pulmonary nodules may be benign or malignant. Benign etiologies include granulomatous reactions from infection and hamartomas, among others. Malignant causes include bronchogenic carcinoma and metastatic disease. The first step is to review any previous chest radiographs for comparison. Both clinical and radiographic information should be used to determine the likelihood of malignancy. Clinical characteristics of malignancy include patient age over 50, history of smoking, weight loss, and previous malignancy. Cancerous nodules (shown in Illustration A) tend to have large size (greater than 8 mm), "ground-glass" or low density, irregular or spiculated borders, absent calcifications, and doubling time between one month and one year. If the lesion has been stable in size for more than 2 years, malignancy may be ruled out without further testing.

Albert and Russell review the management of solitary pulmonary nodules. Management is determined by the size of the nodule and the patient's risk factors for cancer. Lesions smaller than 8 mm (Illustration B) and those 8 mm or greater (Illustration C) are followed up differently. Lesions that are growing should be biopsied. Detection and treatment of early lung cancer may lead to decreased morbidity and mortality.

The National Lung Screening Trial compared low-dose chest CT and chest radiography for lung cancer screening in individuals with 30+ pack-years of smoking. Low-dose CT screening was found to decrease both lung cancer-specific and all-cause mortality. Increased detection of early lung cancers and decreased detection of advanced cancers were seen in the CT group.

Figure A depicts a chest radiograph with a left upper lobe solitary pulmonary nodule.
Illustration A shows a chest CT scan of a cancerous lesion in the left lung. Note the large size and irregular borders.
Illustrations B and C show the algorithms for follow-up of patients with solitary pulmonary nodules of less than and greater than 8 mm, respectively.

Incorrect Answers:
Answer 1: Given there is not previous films to ensure stability over 2 years, reassurance is inappropriate, as this patient's pulmonary nodule should be monitored for growth to rule out malignancy.
Answers 3 and 4: Bronchoscopy and CT-guided biopsy are methods of obtaining tissue for a definitive diagnosis and would be appropriate for evaluation of a growing lesion.
Answer 5: A PET scan would be useful for providing staging information such as nodal involvement once a diagnosis of malignancy has been established or to evaluate a nodule > 8 mm on CT with intermediate probability of malignancy (based on clinical calculator).